Everyone knows that the ability to communicate is a crucial success skill.  However, what most people don't understand is that communication is mostly listening, according to Ed Hess, author of the book Learn or Die: Using Science to Build a Leading-Edge Learning Organization.

"It used to be that the smartest person in the room was the one who was constantly talking," says Hess, "Today, the smartest person in the room is the one who asks the right questions and then truly listens to what others have to say."

These great communicators know how to listen well, which largely consists of avoiding these all-too-common mistakes:

1. Thinking about your response before the speaker is finished.

Because humans are naturally self-centered, when we listen to other people, our natural tendency is to categorize what we hear according to our preconceived opinions and formulate a response based on those opinions rather than what the other person is actually saying.

For example, a customer might begin a sentence with "I'm having problems with your service department..." at which point you're already thinking of ways to either 1) defend your service department or 2) throw them under the bus to keep the customer happy.

However, that customer might continue with "...because we're not sure how the product is supposed to work." However, you might be so wrapped up in formulating your response that you'll miss that this is actually a request for better training, not better service.

Fix: "Be present, in the moment, with an open mind," explains Hess. "Take two minutes to get into the right frame of mind by taking some deep breaths and saying to yourself, 'Listening is not about me and Slow down. Don't rush to conclusions. Seek to understand.'"

2. Finishing the speaker's sentence out loud or in your head. 

Because our work environments are so fast-paced, it's easy to slip into survival mode, trying to move things along as quickly as possible, even when you need to slow down to handle an important interaction or conversation.

Rather than listening, or even thinking about your response (see #1 above), you may find yourself finishing the other person's sentences in our heads or worse, finishing them out loud. Not only does this show disrespect, much of the time you'll get it wrong.

Using the example above, the customer might begin a conversation with "We've been having some problems with..." and then you think (or blurt out) "service department!" because you've been handling complaint about your service department all day.

Fix: "Whenever you find yourself thinking 'I've heard this a thousand times before,' be aware that you're making assumptions and inferences," says Hess. "Fight it by using exploratory questions to gain a deeper understanding of what the person is saying."

3. Letting your mind wander to something you think is more important.

We all multitask; it's impossible to avoid it in today's work environment. However, numerous scientific studies reveal that multitasking is ineffective and unproductive. That's especially true when multitask your thought processes in the middle of a conversation.

While it's true that other people can be repetitive and boring.  However, most people can sense when you're multitasking your thoughts and, since they know you're not listening, they feel the need to repeat themselves.  Your lack of attention makes them even more boring!

When you take the opposite approach and actually focus intently on what the other person is saying and then actively repeat that back, so they know they've been heard, it trains them to come to the point, which is to the advantage of both of you.

Fix: "Intentionally think about what the other person is saying. Do you really understand? What did he or she really mean?" Hess advise. "Listening is not a competitive process; it is a relational one. It requires exploring another's thinking with an open mind."

4. Offering advice before being asked.

Many people wrongly believe that giving advice is a great way to show somebody that you've heard them out and want to help. However, unless you've been asked for advice, your advice is simply a way for you to validate your own opinions and make yourself feel smart.

Look, your experiences are unique to you. They do not match up to everyone else's reality.  The same thing is true of advice based on your experience. It will be skewed by your preconceived notions and fail to take into account what you don't know.

Just because a colleague or friend shares a story with you doesn't mean they necessarily want your advice. Much of the time, people want someone to hear them out, to truly listen to what they have to say. If they want your advice, they'll ask for it.

Fix: "Well-timed, thoughtful questions will help you better understand what the other person wants and needs," notes Hess. "If you feel that you simply must provide advice, ask whether that advice is wanted.  If the answer is 'no,' then keep your advice to yourself."

5. Critiquing the speaker rather than the idea.

One of the most frustrating experiences in my personal life was being married to a psychotherapist.  Whenever I tried to surface a problem, she deftly and automatically turned the conversation into a critique of the way I was communicating.

I've seen this in business meetings, too. I once watched a group of marketers rake a programmer over the coals because his presentation was awkward, even though his ideas were actually quite good (although contrary to the marketing group's strategy.)

As Hess points out, "by critiquing the speaker instead of the idea, we're really seeking to discredit them in order to invalidate their idea, hoping our own idea will rise to the top." While that sounds like a good strategy, it's actually very stupid.

First, the speaker you're attacking will naturally resent you. Second, and more important, any of your colleagues who aren't mental dwarfs will immediately realize that if your competing idea were any good, you wouldn't be resorting to an ad hominem attack.